Samuel C E, Murray C L, Rabinowitz J C
J Bacteriol. 1973 Oct;116(1):41-7. doi: 10.1128/jb.116.1.41-47.1973.
The NH(2)-terminal amino acid distribution of Streptococcus faecalis R soluble and ribosomal proteins isolated from cells at different stages of growth on either folate-sufficient or folate-deficient medium was determined by the dinitrophenyl method. The NH(2)-terminal residues do not follow the random distribution observed for the total amino acid composition of S. faecalis soluble and ribosomal proteins. Methionine and alanine occur most frequently; serine, threonine, aspartic and glutamic acids, and glycine are also present at the NH(2)-terminal position of S. faecalis R proteins. The absence of folic acid yields cells that are incapable of formylating methionyl-transfer ribonucelic acid tRNA(f) (Met), but does not affect either the qualitative or quantitative NH(2)-terminal distribution of total soluble or total ribosomal proteins compared to cells grown with folate. A small quantitative difference was observed in the frequency of distribution of certain amino acids at the NH(2)-termini between log and stationary phase soluble proteins. The amino acid residues found at the NH(2)-terminal position of S. faecalis proteins are qualitatively similar to those reported for several other organisms.
采用二硝基苯法测定了从在叶酸充足或叶酸缺乏培养基上处于不同生长阶段的粪肠球菌R细胞中分离出的可溶性蛋白和核糖体蛋白的氨基末端氨基酸分布。氨基末端残基并不遵循在粪肠球菌可溶性蛋白和核糖体蛋白总氨基酸组成中观察到的随机分布。甲硫氨酸和丙氨酸出现的频率最高；丝氨酸、苏氨酸、天冬氨酸、谷氨酸和甘氨酸也存在于粪肠球菌R蛋白的氨基末端位置。缺乏叶酸会产生无法将甲硫氨酰 - tRNA(f)(Met)甲酰化的细胞，但与在叶酸存在下生长的细胞相比，这并不影响总可溶性蛋白或总核糖体蛋白的氨基末端分布的定性或定量情况。在对数期和稳定期可溶性蛋白的氨基末端，某些氨基酸的分布频率存在微小的定量差异。在粪肠球菌蛋白氨基末端位置发现的氨基酸残基在性质上与其他几种生物体中报道的相似。
